Television system



Julj'Sl, l-Qf `A. N. GoLDsMlTH Er AL. 1,770,205

TELEVISION SYSTEM Filed March 25, 1929 Vim ma ALFRED N. GOLDSMITH JULIUSWEINBERGER 35% mmm-mw l mann N. lninnsln'r'n Nn mms WEINBERGEB, on NEWPatented July 8, 1930 11,7,1o,g o5 Y UNITED Y STATES PATENTfoFF1cn- Non,N. Y., AssIGNons @REVISION sys'rnilr" Application led Hai-oh 25, 1929.Serialv No. $49,652.

The present invention relates to television systems andmore particularlyto television systems wherein the television signal, the synchronizingsignal and a speech signal accompanying the television signal are alltransmitted simultaneously.

In the mostv practical and commercial developments of the various typesof television s stems it has been found necessar and desirable totransmit a synchronizing requency which, for example, may consist of anaudio frequency tone transmitted simultaneouslyv with the ltelevisionsignal. This is necessary so that proper synchronization between thetransmitter and receiver of a television system is maintained and thenecessity of constantly framing the received picture by manual means isavoided. When the synchronizing signal is transmitted 'absolute constantframing of the received picture is obtained and all hunting in theapparatus is avoided. It is also. desirable at most times to send aspeech or music accompaniment on the same channel with the televisionsignal so that the sight of the received picture may be accompanied byspeech or music occurring simultaneously with the various movements oractions in the received icture.

Therefore, one o the principal objects of the present invention is toprovide-a method and arrangement for accomplishing all of these abovenamed desirable results simultaneously. v A further object of ourinventionis'to provide a method and apparatus whereby the television andsound transmission channel-l; may be so arranged that the combined widthi thereof Will not exceed 100 kilocycles. This band width has been foundto be most advantageous from the point of view of convenience andeconomy of wave channels.

Other and ancillary objects of our invention will at once suggestthemselves to those skilled in the art to which the invention relates byla reading of the following specification in connection with theaccompanying y diagrams, wherein:

Fi 1 shows an arrangement by which it is possi le to bring thetelevision, the speech and the synchronizing si als all within a 100kilocycle band;

Fig. 2 conventionally illustrates one form of,4 transmitting apparatusfor accomplishin the results lllustrated by Fig. 1; and,

ig 3 conventionally illustrates a receiv- `ing system which may be usedin cooperation with the transmitter shown by Fig. 2. s

Now 'making reference to the accompanying drawings, it will be notedfrom Fig. 1 that the television signal is 43 kilocycles wide and thatwhen using both side bands thereof the space occupied for the televisionsignal is, in all, 86 kilocycles. The voice and synchronizingfrequencies are, according to the present invention, distributed about acarrier frequency located at 50 kilocycles, for example, from thetelevision carrierv frequency.

It has been found in commercial practice that by providing for speechvarying from 0 to 5 kilocycles most satisfactory results are obtainable.These speech frequencies up to 5l kilocycles may then be used tomodulate the speech carrier located at approximately 50 kilocycles fromthe television carrier frequency a sinle 6 kilocycle tone may beimpressed for t e purpose of obtaining proper synchronization betweenthe transmitter and receiver.v

While, for the purpose of giving'concrete illustrations of one form ofour invention, wevk have l villustrated and assigned. definite valuesvtothe various carrier frequencies and wavebandS, itis,4 of course, tobe recognized thatntlies'efvalues maybe varied within widelimitationslwithout departing from the-spirit andscope of theinvention,and that all values ofI frequencies illustrated and described are toberegarded as merely illustrative and not limiting. y

Now referring to Fig. 2, showing alform of the transmitter apparatus, ldesignates an arrangement,.- such as appropriately connectedphotoelectric elements for picking up the television signal. Thistelevision signal is then preferably .used to modulate, by means ofmodulator 3, a` carrier frequency of 2043 kilocycles generated by agenerator 5 of any desiredand suitable character. It will be `noted thatthe generator fr uency has been -chosen as 2043 1n a purely ar itrarymanner,

being equal to 2000 kilocycles plus the 43 kilocycle modulation so as tobring the lower limit of the modulated carried frequency as 2000kilocycles and the upper limit thereof to 2086 kilocycles, for thepurpose of bringin Vthe illustrated television signal wave ban limpressed upon a microphone and amplifier or any other suitable arranement 7 and passed therefrom through a ltering ap ratus 9 which assesferquencies varying tween zero ang 5 kilocycles chosen for the s echchannel.A Similarly, a 6 kilocycle sync ronizing tone is produced by anyconvenient form of arrangement, diagrammatically shown as 11, and boththe speech or voice and the synchronizing tones are then applied andused to modulate through modulator 12 a second carrier frequency whichmay be, for example, 50 kiloc cles produced by a generator 13 of anysuita le and desired character.

The 50 kilocycle carrier, when modulated by both the voice and thesynchronizingtone, is then, in turn, applied through filter 14 passingfrom 44 to 56 kilocycles by means of the modulator arrangement 3 so asto modulate the previously described 2043 kilocycle carrier frequency.This modulation will then lproduce the voice and synchronizing side andsexisting about a second carrier frequency of a value of 2093 kilocycles,and also produce the same effect about a carrier located at1993'kilocycles but, as shown conventionally by the diagrammaticillustration at 15, there is provided an output filter 15 which passesonly frequencies varying between 2000 kilocycles and 2100 kilocycles, sothat the lower side band of the carrier frequency 2043 modulated by the-50 kilocycle generator, which is in turn modulated by both voice andthe synchronizing tones, is cut off and only Lone side band existing at2093 kilocycles is transmitted.

Modulators 3 and 12 are of a type which will prevent the side bandfrequencies from beating together. For example in the case of modulator12 the input `frequencies are 0-5 kilocycles, 6 kilocycles, and 50kilocycles. The output frequencies to the filter 14 are 44 kilocycles,45-50 kilocycles, 50-55 kilocycles, and 56 kilocycles. The frequencieswhich would be obtained if 0-5 kilocycles beat with the 6 kilocycles, donot exist.

It will thus be seen that, from the antenna system17, signals varyingbetween 2000 and 2100 kilocycles are transmitted. These signals may bereceived in any appropriate manner by a receiving system, for example,of

the type conventionall illustrated by Fig. 3 of the accompanyingrawings.

Signals transmitted from the transmitter of Fig. 2 may be received bymeans of -a receiving antenna system 19 andy directed therefrom througha filtering and amplifying apparatus 21. The filter 21 is preferably soadusted that it asses frequencies varying only etween 2000 ilocycles and2100 kilocycles. Connected with the output of the filter and amplifyingapparatus 21 is a detector 23 to which a frequency corresponding to thecarrier frequency for the television signal, namely, 2043 kilocycles isapplied by means of generator 25.

The output from the detector 23 is thenpassed through two separatefiltering systems, one, being for the television sig nal channel and theother, B, being for the voice and synchronizing signal channel.

In channel A, for the television signal, we have provided a filtersystem 27 so arranged as to pass frequencies varying between zero and 43kilocycles and the output of this filter is then passed through inappropriate form of amplifying arrangement 29 for the purpose ofamplifying the television signals, and the amplified signals are thenimpressed upon a television indicator 31, which may be, for example, aneon glow lamp (not specifically shown), arranged to produce a glowbehind1 the usual type of`Nipkow disk, for exam e.

n the channel B we have provided a filtering system 33 arranged to passfrequencies varying, for example, between 43 and 57 kilocycles whichwill cover the band required for the modulation produced by both thespeech or' voice fre uency and the synchronizing frequency. rom theoutput of this filter 33 the'speech and synchronizing energy is passedto a detector 35 upon which is impressed tlie frequency of a localoscillator at 50 kilocycles, so as to beat with the impressedfrequencies of 43-57 kilocycles. Any ap ropriate form of generator 37may be providbd for generating the 50 kilocycle tone.

The beat frequency output from the detector 35 is then directed to anamplifying system 39 from which it is applied to a pair of tplarallellyconnected filters 41 and 43. The

lter 41 is preferably a lowv pass filter arranged to pass between zeroand 5 kilocycles and then direct its output to any appropriate form ofspeech indicating apparatus 45, for example, a loud speaker, and theoutput of the 6kilocycle band pass filter 43 may be applied and directedto any appropriate form of synchronizing arrangement, for example, anarrangement of the type claimed and described by co ending applicationof T. A. Smith, Serial o. 322,704, filed November 30th, 1928 (Dkt. No.3107 for the purpose of synchronizing the receiving arrangement withthat of the transmitter.

the 2093 kilocycle carrier is transmitted, but

if the 2093. carrier frequency above described is not transmitted as,for example, in a balanced amplifier or su pressed carrier frequencysystem, then, o course, it will be recognized that the local oscillator37 is essential tothe system.

In addition, it will be recognized that various modifications of thescheme herein disclosed may be provided and these, for example, mayconsistin connecting a. circuit broadly tuned to frequencies varyingbetween 2000 kilocycles and 2100 kilocycles to the receiving antennasystem 19, and then detecting these signals and tothe output of thedetecting system connecting a filtering system passing a maximum of 43kilocycles. By means of appropriate amplifiers these frequencies may beused to produce thetelevision image at the receiver.

Also, connected to the output of the detector, last described, we mayprovide, if desired, a secon'd circuit tuned to frequencies varying by6or 7 kilocycles in either direction from the 50 kilocycle frequencyproduced at the receiver. These signals are then detected in the usualmanner and the output from this 'second detector may then be connectedwith a band pass filter passing from zero to 5 kilocycles for the speechfrequency and also connected with a sharply tuned circuit tuned to the 6kilocycle synchronizing signal. It will, of course, be recognized thatcertain disadvantages are inherent in a system of the last named typesince the energy of the voice and synchronizing signals is substantiallydecreased and in the event of bad fading conditiors, these signals mightbe totally obliterate Also, as a further modification, it would bepossible to couple with the receiving antenna 19 a filter system passingbetween 2000 kilocycles and 2086 kilocycles for the purpose of obtaininga television signal and also parallelly connecting a second filteringand amplifyin system in Which the lilter was tuned 2093 ki ocycles plusor minus the 6 kilocycle modulation impressed thereon for obtaining thevoice and synchronizing signals in a manner similar to that lastdescribed.

It is also conceivable that we may provide, if desired, at thetransmitter a filtering system arranged to cut oif at 2043 kilocycles,for example, should this be desirable, and thus only transmit a singleside band of the .television signal although with filtering systemsarranged to give a sharp cutting off at the lower and upper limits thisis not essential since the modulation about 1993 kilocycles signal innowise effects the'television signals, since .the voice andsynchronizing signals are not capable of modulating each other by crossmodulation effects to any appreciable extent. v

While we have used the terms speech, voice, and music as forming thesounds accompanyin the television signals and related thereto 1t shouldbe understood that these terms are intended to include sound of everytype and description, whether produced naturally or artificlally.

However, arrangements falling within the scope of the present disclosurewill atl once suggest themselves to those skilled in the art and we,therefore, desire to be limited` in the arrangements which We may useonly in so far as the scope of the hereinafter appended claimsnecessltates and We may feel free to make any and all modifications ofthe invention falling fairly within the spirit and scope of thehereinafter appended claims. .Y

Having now described our invention what We claim and desire to secure byLetters Patent is the following:

1. In a television system, means for pro'- ducing and transmitting'television signals lying Within relatively large proportion of apredetermined and chosen wave band, means for simultaneously producingand transmitting speech signals lying within a relatively small portionof the said. predetermined chosen wave band, andmeans for simultaneouslyproducing and transmitting syn-v chronizi-ng signals occupying a minuteportion of said predetermined chosen wave band.

2. In a television system, means for producing television signalsfalling Within predetermined frequency range, means for smultaneouslyproducing speech signals to a c company the television signals, andmeans for also simultaneously producing a syn-y chronizing frequencyaccompanying both said television signal frequency and said speechsignal frequency, means for simultaneously transmitting all of-saidtelevision, speech and synchronizing signal frequencies, and means forreceiving and distinguishing between each of said various frequencies.whereby the synchronizing signal frequency controls the synchronizationof the television signal at the transmitter and receiver and the speechsignals accompany the television signal as the same is received.

3. A system for simultaneously receiving speech, televisiony andsynchronizing signals all of which are produced and occur within apredetermined chosen frequency band,which includes, means for selectingreceived signals falling within the said predetermined' frequency band,means for determining and selecting the television signal from saidfrequency band, means for jointly selecting and distinguishing thespeech and synchronizing frequency from said predetermined frequenc bandand means for ltering and distlnguishmg between the said speech andsynchronizing frequencies, whereby the synchro'- ,said first name nizingfrequencies control the chronization of the television signals an thespeech signals accompany the television image as reproduced in propertime relationship.

4. In a television system, means for producing television signalsvarying in frequency over a. predetermined frequency band, means forproducing a carrier frequency, means for modulatin said carrier requencyby said televisionv slgnals, means for producing speech signalssimultaneously with the production of said television signals, means forproducing a synchronizing signal frequency for maintaining synchronismin said television system, means for producing a second carrierfrequency, means for modulatin said second carrier frequency by saidspeec and voice frequency, and means for modulatin frequency by saidlast named modulated second carrier frequency, and filtering means foreliminatin one side band produced by frequency modulated by saidsecondary modulated carrier fre uency, and means for transmitting all ofsai signals simultaneously within a predetermined frequency band.

5. In a television system, means for producing a carrier frequency,means for producing television signals and modulating said carrierfrequency therefrom ina manner such that the modulated carrier covers arelatively large portion of apredetermined frequency band for thetelevision signal, the

- speech signal accompanying the same and a synchronizing signalfrequency Afor maintaining synchronlzatlon 1n the said televisionsystem, means for simultaneously producing speech and synchronizingsignals and modulating the said carrier frequency thereby in a mannersuch that the modulation produced by said s ech signals and saidsynchronizing signa s lies external to the frequency band covered bysaid television signals, and means for transmitting the said signals.

6. The method of simultaneously transmitting television, speech andsynchronizing signals all lying within a predetermined chosen frequencyband, which includes, modulating a carrier frequency by televisionsignals varying over a predetermined frequency band, producing asecondary carrier frequency, modulating said secondary carrier frequencyby a speech frequency varying over a predetermined frequency range andby a synchronizing frequency of constant value, modulating sa1d firstnamed carrier frequency by said speech and synchronizing signalmodulated secondary carrier frequency, limiting the frequency bandcovered by said doubly modulated carrier frequency, and transmitting thesaid television, speech and synchronizing frequencies all Within apredetermined chosen frequency band:

7. In a television system, a combination in turn said first namedcarrier of a transmitter and a receiver, and means for simultaneouslytransmitting from said transmitter televislon, speech and synchronizinsignals all lying within a predetermined chosen frequency band, andmeans for receiving and distinguishing between all of said television,speech and s nchronizing signals at the receiver, whereby televisionimages are produced at the receiver and synchronized with the movementsof the television Subj ect at the transmitter, and the speech record issimultaneously transmitted and received so as to bring the speech recordin proper phase relationshi with the movements of the television suject.

8. In a television receiving system for receivingcombined television,speech and synchronizing frequencies all lying within a predeterminedwave band, means for receiving signals and limiting the receptionthereof to the predetermined chosen fre uency band means for detectingall of said signals and filtering the same to separate televisionsignals from the lspeech and s nchronizing signals, means for detectingtile speech ,of synchronizing signals, and means for filtering therectified output of said last named detector and a distinguishingbetween the s eed and synchronizing signals, whereby sync ronization ofthe television signal'is obtained from the synchronizing signal and asound record occurring simultaneously with the television signal isproduced by the speech frequency.

9. In a television system, means for simultaneously receiving combinedtelevision, synchronizing and speech signal, means for detecting each ofthe received signals, filter means for separating each of said signalsone from the other, and means for am lifying each of said signals andproducing flf'om the same a television image, synchronized movements ofthe television image, and an accompanying speech record.

10. In a television and sound transmission system having the signalsconfined Within a continuous frequenc band, means for producing andtransmitting television signals grouped about a predetermined carrierfrequency and occupying a relatively large portion of the frequencyband, and means for simultaneously producing and transmitting relatedsound signals grouped about a second predetermined sound carrierfrequency separated from the television carrier and adjacent thereto andarranged to occupy a relatively small portion of the said frequencyband. Y

1l. The'combination claimed in claim l0 including, in addition, meansfor producing and transmitting synchronizing signals grouped about saidsound carrier so as to occupy the upper and lower limits of thefrequency band selected therefor.

12. In a television system, means for simultaneously receiving combinedtelevision, synchronizing and sound signals each 0ccupying pre-assignedportions of a selected frequency hand, means for distinguishing betweeneach of said television, sound and synchronizing signals for separatingeach from the other, and means for producing from all of said signals atelevision image synchronized with the transmitted image and anaccompanying sound record.

. ALFRED N. GOLDSMITH.

J'ULIUS WEINBERGER.

DISCLAIMER amaca-142mm. Goldsmith and Julius Weinberger, New YofkfN. Y.TELE- sIN SYSTEM. Patent dated July 8, 1930. Disclaimer filed May 1 8,1932, by the patentees, assignee, Radio Um'pomtofn of America,assenting.

Disclaim from the scope of claim 10 in the above named patent alltelevision sound transmission systems except those systems wherein thesound signals related to the tele- Vision signals occupy a relativelysmall, single and continuous portion of the entire continuous frequencyband for both television and sound signals, and wherein the soundfrequency signals arel adjacent to, or adjoin, the television signals onone slde

